The present invention relates to a method for recording a selectable process signal of a system, and more particularly to a method for recording process signals as a function of system variables other that the timing signal of the system.
Certain functions, sometimes also referred to as trace functions, are employed in drive controllers and other types of controllers which store selectable process signals indexed by a clock signal, typically having equidistant time intervals. Either temporal functions or, after a transformation, frequency functions are recorded.
Functions to be recorded that do not depend on the time, but from other process variables, still have to be stored with a time index as independent variable. Due to the limited number of memory locations, measurements can only be recorded over a limited time, which may prevent significant mutual dependencies of the process signals to be inferred. It is then also not possible to directly average the process signal to be recorded with respect to the index-forming signal in the trace memory.
For this reason, external auxiliary devices with special functionality are frequently employed to process the measurement values.
It would therefore be desirable and advantageous to provide a trace function which allows indexed measurement values to be stored independent of a time index. It would also be desirable and advantageous to directly average a process signal to be recorded with respect to an index-forming signal.